It's a tricky one. When my DS1 started prep he loved to hang out with the grade 6 boys. They'd let him play 2-square with them and would high-five him, etc. It was kind of cute! The novelty does wear off and he found friends his own age too.

Our school are now strict and have two areas at recess - one for prep to Grade 2 and one for Grades 3-6. DS1 is in Grade 3 and is so sad that he's not allowed to go see his little brother who started prep this year. The older kids were told that the preppies need to find friends their own age and that's why they're not allowed over there. I guess it makes sense, but it's a little sad that my boys can't say hello at lunch time.

Hopefully your DD will find some good friends closer in age as the year goes on.